NOAA Technical Memorandum NMFS-SEFSC- 463 Acoustic and Visual Survey of Cetaceans in the Waters of Puerto Rico and the Virgin Islands: February – March 2001 Steven L. Swartz, Anthony Martinez, Jack Stamates, Carolyn Burks, and Antonio A. Mignucci-Giannoni 70° 69 ° 68° 67° 6 6° 65° 64° 63° 21° 21° N W E 20° 20° S 19° 19° 18° 18° 17° 17° 16° 16° 70° 69 ° 68° 67° 6 6° 65° 64° 63° U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Southeast Fisheries Science Center 75 Virginia Beach Drive Miami, Florida 33149 January 2002 Acoustic and Visual Survey of Cetaceans in the Waters of Puerto Rico and the Virgin Islands: February – March 2001 Steven L. Swartz and Anthony Martinez Southeast Fisheries Science Center, NOAA Fisheries, Miami, Florida, USA Jack Stamates Atlantic Meteorological and Oceanographic Laboratory, NOAA, OAR, Miami, Florida, USA Carolyn Burks Southeast Fisheries Science Center, NOAA Fisheries, Pascagoula, Mississippi, USA Antonio A. Mignucci-Giannoni Caribbean Marine Mammal Laboratory Universidad Metropolitana, San Juan, Puerto Rico U.S. DEPARTMENT OF COMMERCE Donald L. Evans, Secretary National Oceanic and Atmospheric Administration Scott B. Gudes, Under Secretary of Oceans and Atmosphere NOAA Fisheries William T. Hogarth, Assistant Administrator for Fisheries January 2002 This Technical Memorandum series is used for documentation and timely communication of preliminary results, interim reports, or similar special-purpose information. Although the memoranda are not subject to complete formal review, editoral control, or detailed editing, they are expected to reflect sound professional work. NOTICE NOAA Fisheries does not approve, recommend or endorse any proprietary product of material mentioned in this publication. No reference shall be made to NOAA Fisheries or to this publication furnished by NOAA Fisheries, in any advertising or sales promotion which would imply the NOAA Fisheries approves, recommends, or endorses any proprietary product or proprietary material mentioned herein or which has as its purpose any intent to cause directly or indirectly the advertised product to be used or purchased because of this NOAA Fisheries publication. This report should be cited as follows: Swartz, S.L., A. Martinez, J. Stamates, C. Burks, and A.A. Mignucci-Giannoni. 2001. Acoustic and visual survey of cetaceans in the waters of Puerto Rico and the Virgin Islands: February-March 2001. NOAA Technical Memorandum NMFS-SEFSC- 463, 62 p. This report has an internal document number PRD-01/02-01. Copies may be obtained by writing: Director, Protected Resources Branch or National Technical Information Center Southeast Fisheries Science Center 5825 Port Royal Road NOAA Fisheries Springfield, VA 22161 75 Virginia Beach Drive (703) 605-6000, (800) 553-6847 Miami, FL 33149 Http://www.ntis.gov/numbers.htm Summary A visual and acoustic survey for humpback whales and other cetaceans was conducted from 12 February to 8 March 2001 in the waters to the east of the Bahamas and around Puerto Rico and the Virgin Islands. The survey utilized passive acoustic techniques (directional sonobuoys and a towed hydrophone array) to augment traditional visual surveys for cetaceans. Several previously unreported areas of humpback whale aggregation were discovered around Puerto Rico, off the east coast of the Dominican Republic, and east and southeast of the Virgin Islands. Samples of humpback whale song were obtained for stock analysis. Additional recordings from sperm whales, other cetaceans, and Atlantic thump trains were obtained. Lists of the species encountered and their distributions, and sounds recorded are presented in 4 tables and 24 figures that accompany the text. -i- CONTENTS Page INTRODUCTION..................................................................................................... 1 BACKGROUND....................................................................................................... 1 METHODS................................................................................................................ 3 Survey Track and Timing.............................................................................. 3 Visual Survey................................................................................................. 3 Acoustic Survey............................................................................................. 4 Sonobuoys.......................................................................................... 5 Towed Hydrophone Array................................................................. 6 Autonomous Acoustic Recorders...................................................... 6 RESULTS Visual Surveys............................................................................................... 7 Estimation of Abundance................................................................... 7 Acoustic Surveys........................................................................................... 7 Humpback Whale Detections............................................................ 8 Sperm Whale Detections................................................................... 10 Atlantic Thumptrains........................................................................ 10 Anthropogenic Noise ....................................................................... 10 Autonomous Acoustic Recorders.................................................................. 11 DISCUSSION Visual and Acoustic Detections..................................................................... 11 Humpback Whale Distribution...................................................................... 12 Atlantic Thumptrains..................................................................................... 13 Anthropogenic Noise .................................................................................... 14 Autonomous Acoustic Recorders.................................................................. 14 Future Surveys.............................................................................................. 15 ACKNOWLEDGMENTS......................................................................................... 17 LITERATURE CITED.............................................................................................. 18 TABLES AND FIGURES......................................................................................... 22 -ii- Acoustic and Visual Survey of Cetaceans in the Waters of Puerto Rico and the Virgin Islands: February – March 2001 INTRODUCTION Marine mammals are protected in U.S. waters (State, Territorial, and U.S. Exclusive Economic Zone) under the Maine Mammal Protection Act (MMPA, 16 U.S.C. 1361 et seq.), and the Endangered Species Act (ESA, 16 U.S.C. 1531 et seq.). The 1994 Amendments to the MMPA require NOAA Fisheries (NMFS) to monitor trends in abundance and distribution of all marine mammals in U.S. waters. Similarly, the ESA requires monitoring of endangered and threatened marine mammal populations in U.S. waters until such time as their populations recover and are removed from the list of endangered and threatened wildlife. The NMFS’ Southeast Fisheries Science Center (SEFSC) developed a scientifically based survey program to provide statistically reliable information on the status of these protected living marine resources on a long-term basis to implement the status of stocks requirement of the 1994 amendments to the MMPA. This information is needed to detect and identify significant changes in the seasonal abundance and distribution of marine mammals that may be indicative of human related disturbance and natural population cycles. This report presents the findings of a vessel based visual and passive acoustic survey for cetaceans conducted from February 12, 2001 to March 8, 2001 in the waters of the northeastern Caribbean including Puerto Rico and the Virgin Islands. BACKGROUND At least 13 species of odontocete and four species of mysticete cetaceans are found in the waters of the Puerto Rican bank, which includes Puerto Rico and the U.S. and British Virgin Islands (Erdman, et al. 1973, Mignucci-Giannoni 1998). The seasonal abundance and distribution for most of these species in the northeastern Caribbean are poorly known (Roden and Mullin 2000, Mignucci-Giannoni 1989, Mignucci-Giannoni et al. 1999). One exception is the endangered North Atlantic humpback whale (Megaptera novaeangliae) which migrates in winter to breeding grounds in and around the Greater and Lesser Antilles (Clapham and Mead 1999, Swartz et al. 2001). The North Atlantic humpback population as recovered from commercial exploitation to an estimated 10,500 animals (Smith et al. 1999), however it remains listed as endangered under the ESA. The largest known and best studied winter concentrations of humpback whales presently occur in the waters of Silver and Navidad Banks off the northeastern coast of Dominican Republic and northern part of the Antillean chain. There, hundreds of humpbacks gather from January to March each year to breed and give birth to their calves (Balcomb and Nichols 1982, 1 Whitehead and Moore 1982, Winn et al. 1975, Whitehead 1982, Mattila et al. 1989). Lower densities of humpbacks have been reported in adjacent areas immediately to the east, including the Mona Passage (Puerto Rico), and the Virgin Bank and Anguilla Bank (Mattila and Clapham 1989). The endangered sperm whale (Physeter macrocephalus) is the second large cetacean most frequently seen in the northeastern